public Messages Update(string pid, long seqNr, Func<IPersistentRepresentation, IPersistentRepresentation> updater)
{
LinkedList<IPersistentRepresentation> persistents;
if (Messages.TryGetValue(pid, out persistents))
{
var node = persistents.First;
while (node != null)
{
if (node.Value.SequenceNr == seqNr)
node.Value = updater(node.Value);
node = node.Next;
}
}
return _messages;
}